Ross Ulbricht, a California man whose 2013 arrest brought notoriety to sprawling black markets in contraband thriving in a dark corner of the web, will go on trial in Manhattan Tuesday on charges that he headed the online drug bazaar known as "Silk Road."

Federal prosecutors claim that Ulbricht, 29, operating under the alias "Dread Pirate Roberts," ran a site with 900,000 users that hosted $1 billion in sales, using bitcoins and an encrypted section of the Internet to cloak sales of cocaine, opioids and other drugs.

In addition to the drug and conspiracy charges, U.S. District Judge Katherine Forrest ruled last week that she will allow prosecutors to try to prove their case by presenting evidence that Ulbricht discussed six different murder-for-hire plots to protect Silk Road.

The judge rejected defense arguments that the evidence should be kept out because the plots were not carried out and the allegations would distract jurors from a trial that is supposed to be focused on a drug conspiracy.

"Ulbricht is charged . . . with designing and operating an online criminal enterprise of enormous scope, worldwide reach, and capacity to generate tens of millions of dollars in commissions," the judge wrote. "Evidence that defendant sought to protect this sprawling enterprise by soliciting murders for his is . . . not unduly prejudicial."

Ulbricht allegedly ran Silk Road from 2011 until 2013. He does not concede that he is "Dread Pirate Roberts" -- the online pseudonym of the operator of the Silk Road site, taken from a character in the movie "The Princess Bride." Prosecutors say they can prove his identity based on evidence on his computer.

Ulbricht's lawyers, in pretrial filings, have also argued that he provided a website no different from eBay, and the government can't show that he became part of a conspiracy or formed a criminal intent just because users of his site engaged in their own drug deals.

"No landlord has been prosecuted under the federal controlled substances statutes for renting an apartment to a known drug seller," defense lawyer Josh Dratel said in one motion. "Nor has any Internet service provider been prosecuted because users of the service engage in illegal transactions using the provider's Internet service."

Dratel did not return a call for comment on Monday.

Ulbricht faces up to life in prison on five separate conspiracy counts -- for narcotics trafficking, computer hacking, money laundering and trafficking in false identification documents -- as well as drug distribution.

He is charged in a separate indictment pending in Maryland with one of the murder for hire plots. In November, Manhattan prosecutors filed charges against another California man alleging that a new "Silk Road 2.0" site catering to drug sellers had been set up in the wake of Ulbricht's arrest and jailing.

Prospective jurors in Ulbricht's case have already filled out questionnaires, and the trial is scheduled to begin after jury selection is completed on Tuesday.